An example of a conventional slitter scorer on a corrugate machine for cutting or scoring a sheet of continuously moving cardboard in the direction of movement is shown in FIG. 5.
The apparatus shown in FIG. 5 is an apparatus for determining positions of heads wherein it is so constructed that a plurality of heads 2 are slidably mounted on shafts 1 and 1a and each of the heads 2 can be located at a voluntary position on the shafts 1 and 1a by repeating the operational steps of displacing the heads 2 on the shafts 1 and 1a by means of shifters 3 and 3a individually or as a group comprising more than two heads and parting away from the shifters 3 and 3a one head at the rearmost end among the heads 2 when the shifters 3 and 3a reach a predetermined position (refer to Japanese Publication Patent NO. 50667/1976).
The shifters 3 and 3a have screw shafts 5 and 5a extended therethrough and the screw shafts 5 and 5a are rotatably supported on frames 4 and 4a. The screw shafts 5 and 5a have sprockets 6 and 6a at the one end thereof so that they are rotationally driven by means of a motor 8 via chains 7 and 7a. Accordingly, as the screw shafts 5 and 5a are rotated, the shifters 3 and 3a are displaced on the screw shafts 5 and 5a so as to displace the heads 2.
FIGS. 6 and 7 are a cross-sectional view of the apparatus taken in line X--X in FIG. 5 respectively, illustrating the structure of the shifters 3 and 3a in different operational states.
The shifters 3 and 3a are pivotally provided with arms 9 and 9a at both the ends thereof. Air cylinders 10 and 10a are pivotally attached to the arms 9 and 9a at the one end and abutment plates 11 and 11a are fixedly attached to the same at the other end thereof.
As shown in FIG. 6, when the heads 2 are displaced, the air cylinders 10 and 10a are actuated and the arms 9 and 9a are closed, causing the abutment plates 11 and 11a to contact the head 2. Thereafter, the shifters 3 and 3a and the head 2 are displaced toward the controlling side A. When the heads 2 reach a predetermined position, rotation of the motor 8 is interrupted and thereby movement of the shifters 3 and 3a are interrupted.
Next, the air cylinders 10 and 10a are actuated and the arms 9 and 9a are opened to assume an inoperative state as shown in FIG. 7. While the arms 9 and 9a are kept in the opened state, the shifters 3 and 3a are displaced toward the controlling side A by a distance equal to the length of one head 2 and by actuating the air cylinder 10 and 10a again, the arms 9 and 9a are closed to assume the operative state as shown in FIG. 6. Thus, the shifter 3 and 3a displace the heads 2 toward the next predetermined position. By repeating the abovementioned operations, a number of heads 2 are successively located at their predetermined position. Incidentally, operations of the motor 8 and the air cylinders 10 and 10a are properly controlled by means of a control unit which is not shown in the drawings.
Since the above-describe slitter scorer is so constructed that the shifter pushes the rearmost end of the heads with the aid of the arm and abutment plate to displace the heads, it is not provided with any stopper for forcibly stopping inertia movement of the heads when the shifter decelerates and stops its movement. Accordingly, to inhibit an occurrence of inertia movement of the heads, arrangement is made such that the shifter decelerates from its high speed moving state, moves at a lower speed at which the heads does not carry out inertia movement, and then stops its movement. As a result, it has been found as problems that it takes long time for movement at a lower speed and setting time is elongated (For instance, in the case where a slitter scorer has a setting range of 2500 mm and includes fourteen heads, about 60 seconds are required as setting time.).